Retractable arrester gear for aircraft



April 25, 1950 G. PETTY v 2,

RETRACTABLE ARRESTER GEAR FOR AIRCRAFT Filed Feb. 18, 1948 r iants-sh t 1 f/vnwrok 6:040: 0WARO Prrrr G. E. PETTY RE'LMCTABLE msm GEAR FOR nacnm April 25, 1 950 4 sheets-sheet 2 Filed Feb. 18." 1948 April 25, 1950 G. PETTY I RETRACTABLE ARRESTER GEAR FOR AIRCRAFT Filed Feb 18. 1948 v 4 Sheets-Shoat s G. E. PETTY .mc'mauz ARRESTER GEAR FOR AIRCRAFT A ril 25; 1950 1w Filed Feb. 18,1948

4 Sheets-Sheet 4 MUZI VTOR Gawaz [db AIM PUT) Patented Apr. 25 i950 $505,664 RETRAGTABUE ARRESJER GEAR :gppliqggtjgn 18, 1948, ESeri'a WestJLeys, SWiniandfEnlackliilrn @1111 General Air: I o'rporation'of "Great Britain- I On-9,683

n Gregt Blgitain January 7 Q1947 IHi'therto .it has been mo '0 jpsual 'to parry uo arrestriiook externally "fthe fjaircj it 'o yfirhensstbwedj .li fusela e f om W into operative" lbeeniproposedii't QsmQ -J I till jegngther obj'eotfof :thef vide means forfd'ainp "g th move em hook arm" with" respect td' fto tend-to j fzibout its horizdiital' onthe ground or landmg' dok an v the return of the hook arm after a bouii''e.

The foregoing and other objects of the present iret'itio'n' -willbe -eippa'rent i fromlthe fifollowing des'oiiptionf ai pretrred:emboiiimefitnflrfiraeb ableairrester gear;

the accompanying; drawings:

Figure 1 is 1 a :-side -:2- elevation a of ithe; reariziend of 'an fair'craft fuselage awithlipartaof ithesskin broken" awaiy torshowwthecompartment; provided t'o 'receive' andithe' disposition gof2the arresteri-gear.

-' :Eigure 2. is a front-view of onegoftherrload :tak- .:ing brackets 1 with whichi-the retrdctionifimeans of the'arresten'gearqengage.

end of the retractiommeans showing theEmem- .b'e'rs which co -'pe'ra te twith' iathe reload r taking 'Joraekets.

i Figure 4 isa-a*side? eievationashowing theiretraction-Ei lever in rfull dine-:imjoperattive: position rand imchaimlinednitsuietraected pesitlion.'

'2 figure 5 is a side elevation ,on enla rged jseale jof fthe end o'fQthe retrgotiohi lever latndhoqk 'larrn Wfithparits shown in seotion;

2 l in theone direction"eiitendsithe"arrester hook "be of conventional {designbut the iiew rtraetioh and hook provided. With"means-for ejfitingifihe arresting cable after an arrestingopereltion* gs described in the s'peoificatio' ofco-pending piitem application seriil 'No. 293215; filed Februry 18, 1948, now"Pe,-tent No. 2-;479927, based-bfi- Br it- --ish patent -applicajtioh' No.32 6,209i'0f 1947. "ifIhe hookarm i is ireenswinging -with degrees ofi free- ;dom a. about '-.fvertica1 rzand cho'rizontailx r axes .Eafld in LOIdBI .to .::-prei ent the :2 arresting-loads :heing transferred to: theirlever l thei.:sa;me2is; provided ;at:its. free end with laterarextensionsfi, l 6: which drop 1 into brackets 3; I18 Iastmrr the :fusela'geeand itr ansmit the-arresting loads thereto so that? the lever: I is ivirtuallyiunstressed during arresting i3 conditions. i

.In the-preferred embodiment illustrated intthe 1 drawings, 7 the: lever; is a ;box: lever of. reetanguiar :SGCtiOI'L hollowc0nst-ruot-io n1 andwarriesiateaits zf'liee end :an axially movable ipflrt 51H] (seer l figure e i and 5) which telescopes (With respect 3 thereto, being:supportedbyesnveridclosure member I hand :transverse assembly I 32 ,v and is loaded byea spring .13 which.:tends 11-1190 urge =-the ;part z: w ioutwa-rdl'y :to:a controliedmextent. {,Ihe pa-rt Hl' carriesma I member-c; M fo r ireerangular: movement withmaspect thereto about a horizontal axis and also laterally extending members I5, I6 each of which is intended to engage in a slot I1 with straight line sides in a bracket it made fast to the fuselage. One wall is of the slot I1 inclines towards the other wall 29 and terminates in an undercut portion ZI so that the slot I1 is similar to the slot of a bayonet joint. The walls of the slot are desirably thickened in the region of the under' cut portion 2! and this portion of the bracket may be further strengthened by an additional plate 22. With this arrangement, as the laterally extending member I5 enters the slot I1 it rides down therein in contact with the wall i9 and causes axial displacement of the part I against the influence of its loading spring i3 which, when the member I5 reaches the bottom of the slot, forces the same into undercut portion 2I to lock therein and prevents retraction of the lever I.

The inner end of the part I0 is connected as by a tube 23, lever 24, tube 25 and lever 26, all conveniently contained within the hollow construction of the lever I, to the piston rod 21 of a hydraulic jack 28. The piston rod 21 is also connected through a lost motion connection (see Figure 6) to the retraction lever I such that on actuating the jack 28 to retract its piston rod a pull is first exerted on the tubes 23, 25 and levers '24, 26, which pulls back the member I9 to release the lateral members I5, I6 from their engagement in the undercut portions 2| of the slots I1 of the brackets I8 to permit upward swinging movement of retraction lever I after taking up of the lost motion connection of the piston rod 21 with respect thereto on further movement of such piston rod.

The hydraulic jack 28 is conveniently a double acting jack to move the retraction lever I into and out of operative position but in the event of power failure the lever will drop into operative position by gravity. An equivalent device such as an electric actuator of known construction may be used instead of a hydraulic jack.

In order to damp the movement of the hook arm 1 about its horizontal axis, an off set arm 39 is provided fast with the member I 4 and on the end of the retraction lever I is mounted a spring loaded device 3I having at the end of its movable part 32 a transversely extending element 33 which engages in a recess provided in the arm 33. Desirably the spring loaded device 31 is pivoted to the lever I, substantially as illustrated, when its moi-' able part 32 is connected by links 34 which are connected to the part II) conveniently on the transverse axis of the member It. This arrangement is such that with the lever I in operative position with the hook arm 1 extended, the spring loaded device 3| is effective on the arm 30 to tend to urge the member I4 carrying the hook arm 1 into its one limit position about its horizontal axis of movement and so resist any tendency for the hook arm I to swing about that axis as, for example, on the hook 8 contacting the ground or landing deck and to accelerate the return thereof after a bounce. During retraction of the lever I the arm 30 separates from its engagement with the element 33 as may be seen from Figure 4 in the alternative position of the part shown in chain line but the spring loaded device 3| has its movable part kept in operative position by reason of the links 34 ready to re-engage the arm 30 when the parts again assume operative position. Instead of the spring loaded device 3 I, there may be used a hydraulic ram, an oleo pneumatic device,

or other resilient device having a movable part.

The hook arm 1 is also desirably damped against angular displacement from its normally central position about its vertical axis, when the member I4 to which the hook arm I is pivoted for movement about such vertical axis has pivoted to it at a point eccentric to such axis one end of a link 35, which is desirably so constructed that its length may be adjusted and which extends in through a slot in the wall of the hook arm 1 to engage pivotally at 36 with a part 31 which is slidably disposed within the hook arm 1. The part 31 is operatively associated with piston-like members 38, 39 each constrained against movement away from one another and having a compression spring 40 therebetween. The shoulder 31 of the part 31 by engaging the reduced diameter portion 38 of the piston-like member 33 causes that piston-like member to follow the movement of the part 31 when the same is displaced, downwardly as seen in the drawings, against the action of the spring 43 when the opposite end of the part 31 moves idly with respect to the piston-like member 39. A collar 31 fast on the end of the part 31 by engaging the reduced diameter portion 39 of the piston-like member 39 causes the latter to follow the movement of the part 31, upwardly as seen in the drawings, against the action of the spring 40 when the upper end of the part 31 moves idly with respect to the piston-like member 38. Thus movement of the one piston-like member on movement of the part 31 in one direction compresses the spring in the one sense whilst opposite movement of the part 31 with consequent movement of the other pistonlike member compresses the spring 40 in the opposite sense. The eifect of this compression of the spring is to tend to return the displaced piston=like member to its original position with consequent movement of the part 31 and hence tends to restore the hook arm 1 to its central position since a displacement of the hook arm 1 about its vertical pivot virtually alters the length of the link 35 due to its eccentric point of pivoting with respect to the pivotal axis of the hook arm.

The construction of the lever I obviates the necessity of providing guide means as there will be little or no tendency for the retraction lever I and hook arm 1 to sway when retracted in which position the hook 8 is located in the aperture in the fuselage through which its arm 1 moves during extension and retraction, when the hook 8 may enter a fairing 35 which may be of robust construction to serve as a bumper for emergency use, for example, for an aircraft having a tricycle landing gear.

I claim:

1. Arrester gear for aircraft, including a pivoted lever entirely within the fuselage, a spring loaded axially displaceable part at the free end of said lever, a hook arm freely pivoted to said part and extending through an aperture in the fuselage, brackets mounted on said fuselage, elements on said spring loaded part for making latching engagement with said brackets, and power-operated means-engaging said pivoted lever to swing it between alternative positions in one of which said hook arm is extended and in the other of Which it is retracted by a lengthwise movement through the aperture in the fuselage.

2. Arrester gear for aircraft including a pivoted lever within the aircraft fuselage, an arm freely pivoted to the end of said lever and extending through an aperture in said fuselage, a hook arranged on the free end of said arm, means connected to said lever for engaging means on said arm to damp movement of said arm about its axis, load transmitting brackets mounted on said fuselage, elements on said lever for engaging said brackets when said arm is extended into operative position, and means for swinging said lever from a position in which said arm is extended to a position in which it is retracted within the fuselage by a lengthwise movement through the aperture in the fuselage.

3. Arrester gear for aircraft including a pivoted lever entirely within the aircraft fuselage, an arm pivoted to the end of said lever to extend through an aperture in said fuselage for free swinging movement about axes at right angles to one another, a hook on the free end of said arm, resilient means on said lever for engaging means on said arm to damp movement of said arm about one of its pivotal axes, means for damping movement of said arm about its other pivotal axis, load transmitting brackets mounted on said fuselage, projecting elements on said lever for engaging between said brackets when said arm is extended into operative position, and power-operated means connected to said lever for swinging it from a position in which said arm is extended to a position in which it is retracted within said fuselage by lengthwise movement thereof through said aperture in said fuselage.

4. Arrester gear for aircraft including a hollow lever pivoted within the aircraft fuselage, a spring loaded axially displaceable part at the free end of said hollow lever, an arm freely pivoted to said part to extend through an aperture in said fuselage for free swinging movement about axes at right angles to one another, a hook on the free end of said arm, resilient means on said lever for engaging means on said arm to damp movement of said arm about one of its pivotal axes, means for damping movement of said arm about its other pivotal axis, load transmitting brackets mounted on said fuselage, elements on said axially displaceable part for making latching engagement with said brackets when said arm is extended into operative position, means connected to said spring loaded part to displace it to disengage said latching engagement of said elements with said brackets, and power-operated means connected to said lever for swinging it from a position in which said arm is extended to a position in which it is retracted within said fuselage by a lengthwise movement thereof through the aperture in the fuselage.

GEORGE EDWARD PETTY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,399,244 Nicholson Apr. 30, 1946 2,421,739 Albright June 10, 1947 

